Those that believe if you spare the rod, you spoil the child. And those that believe that sort of discipline does more harm than good.

Now one study is looking to end the debate.

An analysis of 50 years of research by experts at the University of Michigan and University of Texas showed no evidence that spanking does any good. Instead, the study found it increases the child’s risk of detrimental outcomes.

"We found that spanking was associated with unintended detrimental outcomes and was not associated with more immediate or long-term compliance, which are parents' intended outcomes when they discipline their children," said Elizabeth Gershoff, associate professor of human development and family sciences at the University of Texas.

The study focused on what most Americans would define as spanking, an open-handed hit on the behind or extremities, and not on potentially abusive behaviours.

Researchers also look at adults who were spanked as children. They found that the more that person was spanked, the more likely they were to have antisocial behaviour and to have mental health issues.

They also found parents who were spanked as children are more likely to support the same type of discipline in their children.

"We as a society think of spanking and physical abuse as distinct behaviors," said Gershoff, who previously taught at U-M. "Yet our research shows that spanking is linked with the same negative child outcomes as abuse, just to a slightly lesser degree."

Researchers say a declining number of parents approve of spanking in the U.S.